Prior posts have addressed the various studies that have been published regarding the impact of exposure to the toxic dust and smoke that was generated by the 9-11 disaster. Researchers have now identified that male firefighters who were exposed to the toxic dust and smoke from the 9-11 attacks have a 19% higher risk of getting cancer of all kinds than colleagues who were not exposed. Given the methodology of the study, these figures will likely increase over time.
9-11 firefighters were exposed to a several known cancer-causing agents, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls, asbestos, and dioxins. Prior studies have shown increased rates of post traumatic stress disorder, asthma, and other respiratory illnesses among rescue workers. To date, only a couple of smaller studies have shown increased rates of cancer, which can take five to 20 years to develop. On the negative side regarding causation, a report in July by the National Institute for Occupational Safety and Health concluded that there was not yet enough evidence to support a causal link between the 9-11 attacks and cancer.
The new study looked at nearly 10,000 male firefighters, providing a huge sample pool from which conclusions could be drawn.
The analytical methodology also provides some support for the conclusion. The researchers only looked at cancers that developed in the first seven years after the World Trade Center attacks, comparing rates among exposed and non-exposed firefighters; as cancers go, this is a truncated time period. The results were also adjusted to exclude information that might skew the results. For example, excluded was data on 576 firefighters who were over age 60 on September 11, 2001, because the small number of men in that age group would have made the results statistically "unstable." Also excluded was data on 32 women, 13 Asians, and 8 native Americans for the same reason, as well as data on 85 men who had a prior cancer diagnosis. After adjusting for these factors, the researchers found the exposed firefighters had a 19% higher rate of having any type of cancer. The study focused simply on cancer, not on any specific type of cancer.
The study did not consider rescue workers; these will be addressed in a separate study.
The study can be found at http://www.sciencedirect.com/science/article/pii/S0140673611609896. The earlier, NIOSH study can be found at www.cdc.gov/niosh/docs/2011-197/pdfs/2011-197.pdf.